About half of the 1.1 million heart attack victims in the United States each year come to hospital emergency departments (EDs). A new study shows that ED doctors miss diagnosing 2 percent of ED patients with heart attack (acute myocardial infarction, AMI) or unstable angina, whom they mistakenly send home. These misdiagnosed patients usually have atypical symptoms that make diagnosis more difficult. These patients have nearly twice the likelihood of dying from their heart problems than similar patients who are hospitalized, notes principal investigator Harry P. Selker, M.D., M.S.P.H., of the New England Medical Center.
In a study supported in part by the Agency for Healthcare Research and Quality (HS07360), Dr. Selker and colleagues prospectively analyzed clinical data on 10,689 patients who sought help at the EDs of 10 U.S. hospitals for chest pain or other symptoms suggestive of a cardiac problem, including 1,855 who met the criteria for AMI or unstable angina. The data were collected during patients' arrival at the ED, during hospitalization (for those who weren't sent home), and 30 days later. Among the 889 patients with AMI, 2.1 percent were mistakenly discharged from the ED; among the 966 patients with unstable angina, 2.3 percent were mistakenly discharged. Patients with AMI or unstable angina who were not hospitalized had nearly twice the odds of dying (odds ratio 1.9 and 1.7, respectively) than patients who were properly diagnosed with these conditions and hospitalized.
The patients whose diagnoses were missed tended to be women under the age of 55; to be black, Hispanic, or another minority; to report shortness of breath as the chief symptom (instead of the typical chest pain); or to have apparently normal electrocardiograms (ECGs). In other words, these patients often did not have typical features of cardiac ischemia. The researchers point out that coronary artery disease is so prevalent that even patients without typical risk factors may suffer from it. They recommend that physicians become more familiar with the atypical symptoms of acute coronary syndromes and be aware of the groups in which such symptoms are especially likely, such as patients who are young, female, diabetic, or very old.
See "Missed diagnoses of acute cardiac ischemia in the emergency department," by J. Hector Pope, M.D., Tom P. Aufderheide, M.D., Robin Ruthazer, M.P.H., and others, in the April 20, 2000 New England Journal of Medicine 342(16), pp. 1163-1170.